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Hundreds of different types of coatings are used to protect a variety of structural engineering materials from corrosion, wear, and erosion, and to provide lubrication and thermal insulation. Of all these, thermal barrier coatings (TBCs) have the most complex structure and must operate in the most demanding high-temperature environment of aircraft and industrial gas-turbine engines. TBCs, which comprise metal and ceramic multilayers, insulate turbine and combustor engine components from the hot gas stream, and improve the durability and energy efficiency of these engines. Improvements in TBCs will require a better understanding of the complex changes in their structure and properties that occur under operating conditions that lead to their failure. The structure, properties, and failure mechanisms of TBCs are herein reviewed, together with a discussion of current limitations and future opportunities.

This book is a review of corrosion and thermal protection topics associated with coatings applied in high temperature applications, namely catalytic converters, combustion and steam environments, and gas turbines. Information on corrosion influencing mechanisms and their impact are reviewed.

This book is an excellent summary of the basic principles of high temperature corrosion; an understanding of which is of paramount importance in understanding the subject. The book begins with the basics of thermodynamics, followed by an up-to-date summary of experimental methods; many of which have not been covered by previous books. The usual supporting topics, such as defect structures in compounds, are presented with great clarity. The book concludes with numerous case-histories which give a good basis for solving practical problems, using the principles expounded in the book. The writers have drawn upon their many years of experience in the field and have provided a most useful book. This work will prove to be an excellent and enduring textbook for graduate courses in oxidation.

This book demonstrates how to counteract the thermal effects of the rapid corrosion and degradation of exposed materials and equipment that can occur under high operating temperatures. This is the first true practical guide on the use of thermally-protective coatings for high-temperature applications, including the latest developments in materials used for protective coatings. It covers the make-up and behavior of such materials under thermal stress and the methods used for applying them to specific types of substrates, as well as invaluable advice on inspection and repair of existing thermal coatings. The author has compiled the very latest in coating materials and coating technologies, as well as hard-to-find guidance on maintaining and repairing thermal coatings, including appropriate inspection protocols. Professional engineers, chemists, physicists and graduate students will benefit from this book.

Solid lubricants are described as solid materials of intentionally introduced or in situ formed on contact surfaces in relative motion for the purpose of lowering friction and wear and providing protection from damage. Solid lubricants and advanced self-lubricating materials are widely used in modern industries, especially in aerospace, aviation, automotive, metallurgy, materials forming, and machining industries, and have attracted great interest in lubrication applications under very severe circumstances such as elevated temperatures, heavy loads, ultrahigh vacuum, extreme radiation, strong oxidation, and chemical reactivity environments. Many efforts have been made to develop self-lubricating composites by a variety of material preparation techniques, which include powder metallurgy, physical/chemical vapor depositions, thermal spraying, electrodeposition, laser cladding, and additive manufacturing. Although several reviews on the development of high-temperature solid lubricants have been published, most of them only focus on a type of material, a specific process, or application. In this paper, a comprehensive review is provided to present the state-of-the-art progress in solid lubricants, self-lubricating composites/coatings, and their effective functions that can be used over a wide variety of environmental conditions, especially at elevated temperatures. The solid lubricants considered include representative soft metals, layered structure materials (e.g., graphite, hexagonal boron nitride, transition metallic dichalcogenides, MAX phase), chemically stable fluorides, binary or ternary metallic oxides, especially alkaline earth chromates, and sulfates, and synergistic effects from these solid lubricants. This paper also provides new insights into design considerations of environmental adaptive solid lubrication, and the challenges and potential breakthroughs are further highlighted for high-temperature solid lubrication applications.

We have determined the upper critical field Hc2as a function of hole concentration in bismuth-based cuprates by measuring the voltage induced by vortex flow in a driving temperature gradient (the Nernst effect), in magnetic fields up to 45 tesla. We found that Hc2decreased steeply as doping increased, in both single and bilayer cuprates. This relationship implies that the Cooper pairing potential displays a trend opposite to that of the superfluid density versus doping. The coherence length of the pairs ξ0closely tracks the gap measured by photoemission. We discuss implications for understanding the doping dependence of the critical temperature$T_{c0}$.

A proton exchange membrane fuel cell (PEMFC), as an efficient energy conversion device, has many advantages, such as high energy conversion efficiency and environmentally friendly zero emissions, and is expected to have great potential for addressing the uneven distribution of global green energy. As a core component, the performance of the proton exchange membrane (PEM) directly affects the overall output of the fuel cell system. At present, Nafion membranes with good, comprehensive properties are the most widely used commercial proton exchange membrane materials. However, Nafion membranes demonstrate a great inadaptability with an increase in operating temperatures, such as a rapid decay in proton conductivity. Therefore, enhancing the overall performance of Nafion membranes under high temperatures and low relative humidity (RH) has become an urgent problem. Although many efforts have been made to solve this problem, it is difficult to find the balance point between high-temperature conductivity and overall stability for researchers. In this paper, we summarize the recent approaches to improving the operating temperature of Nafion membranes from the following two perspectives: (1) using different materials for the modification of Nafion membranes, and (2) applying different modification methods to the Nafion membranes. Based on the structural and functional characteristics of Nafion, the non-destructive targeted filling of fillers and the efficient synergy of the two-phase region are two vital research directions for the preparation of high-performance composite membranes.

The molecular-based magnetic materials Cs$_2$Mn$^{II}$[V$^{II}$(CN)$_6$] (1) and (Et$_4$N)$_{0.5}$Mn$_{1.25}$-[V(CN)$_5$]$\\cdot$2H$_2$O (2) (where Et is ethyl) were prepared by the addition of manganese(II) triflate to aqueous solutions of the hexacyanovanadate(II) ion at 0°C. Whereas 1 crystallizes in a face-centered cubic lattice, 2 crystallizes in a noncubic space group. The cesium salt (1) has features characteristic of a three-dimensional ferrimagnet with a Néel transition at 125 kelvin. The tetraethylammonium salt (2) also behaves as a three-dimensional ferrimagnet with a Néel temperature of 230 kelvin; only two other molecular magnets have higher magnetic ordering temperatures. Saturation magnetization measurements indicate that in both compounds the V$^{II}$ and high-spin Mn$^{II}$ centers are antiferromagnetically coupled. Both 1 and 2 exhibit hysteresis loops characteristic of soft magnets below their magnetic phase-transition temperatures. The high magnetic ordering temperatures of these cyano-bridged solids confirm that the incorporation of early transition elements into the lattice promotes stronger magnetic coupling by enhancing the backbonding into the cyanide π$^*$ orbitals.

Rapid innovations in 3-D printing technology have created a demand for multifunctional composites. Advanced polymers like amorphous thermoplastic polyetherimide (PEI) can create robust, lightweight, and efficient structures while providing high-temperature stability. This work manufactured ULTEM, a PEI-based polymer, and carbon-fiber-infused ULTEM multi-material composites with varying layering patterns (e.g., AAABBB vs. ABABAB) using fused filament fabrication (FFF). The microstructure of fractured surfaces and polished cross-sections determined that the print quality of layers printed closer to the heated bed was higher than layers closer to the top surface, primarily due to the thermal insulating properties of the material itself. Mechanical properties of the multi-material parts were between those of the single-material parts: an ultimate tensile strength and elastic modulus of 59 MPa and 3.005 GPa, respectively. Multi-material parts from the same filaments but with different layering patterns showed different mechanical responses. Prints were of higher quality and demonstrated a higher elastic modulus (3.080 GPa) when consecutive layers were printed from the same filament (AAABBB) versus parts with printed layers of alternating filaments (ABABAB), which showed a higher ultimate strength (62.04 MPa). These results demonstrate the potential for creatively designing multi-material printed parts that may enhance mechanical properties.